Apparatus for fluffing slag



Dec. 8, 1953` T. H. KENNEDY APPARATUS FOR FLUFF'ING SLAG Filed Oct. 26, 1950 [mem: 7z/M4/v/ KEA/Naan #Walla Patented Dec. 8, 19,53

Parana? @Fp-16E# 2,661,575, APPARTUS'FGR FLUFFING SLG Truman.H..rKennedy,.,Elizabeth,TownshipyAllee y ghe'ny Coiinty,".,l?a.`, assignonsto.,UtedsstatesL.. Steel. Corporatioma corporationof Nett'"Jersey" a low moisture content, the proper size gradation,r;-l5

andra desirable coloration..

Fluffedior expanded slag.. is distinguislredrv from ther-f commonly known granulated? slagaibyp :its superiorphysical. properties: arrdzfunifornr.'Icellne4 lar.=:.structure; Granulated Arslagrfiistfra light? tane colored foamy material containing large air cells with a high Water content and a low compressive strength. In contrast thereto, expanded slag is somewhat grey in color having a 10W moisture content, a high compressive strength, and a uniform cellular structure. Granulated slag is made by dumping molten slag into a pit containing water or the slag is poured into a Water-bearing flume. Another method utilizes streams of Water under high pressure against the molten slag as it is poured into pits.

There are several processes known today for the treatment of slag for commercial use, but few make a luffed slag economically suitable for concrete aggregate. All those with which I am familiar, furthermore, are characterized by serious objections from the standpoint of practical operations. The object of the more recent methods of slag expansion has been to secure better control in the rate of cooling from the molten slag to the finished product. Rapid cooling tends to produce a tan-colored granular glassy crystalline structure which is extremely light and brittle Whereas slow cooling, such as air cooling, tends to produce a heavy dark grey cellular slag. Each of these extremes fails to meet the qualications for a good light-Weight concrete aggregate.

I have invented a novel apparatus for flumng slag, the product of which has proved highly satisfactory for use as a light-weight aggregate in concrete. In a preferred embodiment and practice of the invention, I partly ll a series of traveling containers with Wet slag lines and then pour molten slag therein. During continued travel of the containers, the slag is fluffed by the agitation resulting-.trema thefvaperizationfofi ,that Water.A ein the fines by the heat of the initiallwmoltemslagsg When ;the.slaghas been thus-:iiuffed .andzcooled thescontaine-rs. ,are..-dumped successively.. cristo a sizingi screen...n .Thenespassing therethroughare.; Wetted=and-again usedlforfpartly .lling additional .i containerswhile the.v larger. particles are.. collectedn for-..usesastaggregaterf: The..apparatus..preferably,;.

includes ansendlesssohain :ofemolds.-traversinga spaced-sprockets@ hopper for deli-veringawetfness. to the meldsrra. nunnernor launden for; conducting...I

molten, slag ...thereto -and .a conveyorfforreturning.

togthe. Immigrer/.the neslpassingzthrough,thaafores mentionedscreenm.

. A- .complete understanding.: of the. invention man.; be..obtained. from.; the-.following- .detailed descrips,...

tion and explanation thereof which.,referttoltheav accompanying drawings thersinglegureofmhch illustratesdiagrammatically...the.preferred em-M bodiment; of .the apparatusoftmyinvention inside; elevation, with' parts in vertical section.

Referring in detail to the drawing, a plurality of containers or buckets Il) are carried on an endless-chain conveyor trained about spaced sprockets I I and I2. The sprocket I2 is driven at a suitable speed by any convenient means, not shown. A hopper I3 above the conveyor adjacent one end thereof contains a supply of wet slag nes I4 which may be either granulated slag or luffed slag. A paddle-Wheel gate I5 at the bottom of the hopper controls the supply of fines to the molds or containers Ill as they travel below the hopper. This gate is so designed and its operation so correlated with the speed of the travel of the conveyor that the molds are partly lled with a bottom layer of Wet fines as indicated at I6.

A slag runner I'I and trough I8 are mounted on suitable supports (not shown) above the conveyor. The runner is adapted to receive molten slag from a carrier vessel such as a ladle I9 and the trough I8 serves to deliver molten slag to the molds Il! successively, thereby forming a layer 20 on top of the layer of wet fines I6 in each mold. As the travel of the mold continues, the heat of the molten slag in layer 2U vaporizes the water adhering to the fines in layer I6. The resulting steam agitates the molten slag as it rises therethrough from the layer IB, as indicated at 2|. After further travel of the molds, the molten slag becomes completely iluifed as indicated at 22 and, incidentally, is cooled substantially.

As the molds I0 pass around the sprocket I2, the contents thereof are dumped on to a sloping screen 23 of a mesh such as to cause separation 3 of the fines from the larger particles suitable for use as aggregate for concrete. The larger particles roll down the screen into a storage bin or car 24. The fines fall on to a belt conveyor 25 traveling about spaced pulleys 26 and 21, one of which is driven by yany convenient means (not shown). The fines falling on the conveyor 25 are carriedv upwardly thereby and before reaching the upper end of the conveyor are subjected to Water sprays discharged by nozzles 28 mounted above the conveyor. The nes, after being thoroughly wetted by the Water sprays, are discharged into the hopper I3 to form part of the massM from which they are again discharged into the molds I0 as needed for re-use in iiumng addi-V portion thereof continuously from the hopper I3 for other disposition.

Experience has shown that if the containers used for receiving the nes and molten slag are eight inches deep, they should be filled to a level of about four inches with Wet slag iines and that the layer of molten slag poured thereon should' be about two inches deep. This results in a-layer of fluffed slag of about four inches deep. Molten slag iluled to twice its original volume satisfactorily meets the physical requirements for a suitable light-.Weight concrete aggregate as enumerated hereinabove. In any event, the characteristics of the product may be varied as described by controlling the amount of wet nes initially delivered to the molds and the quantity of molten slag poured thereon.

It will be apparent that the method and apparatus of my invention are well suited for exact control of the operation to insure production of uffed slag useful as aggregate. By proper control of the moisture content of the wet iines and the amount of the latter, the proper degree of uflng can be obtained for any given amount of molten slag Within the capacity of the molds or containers. The apparatus involved is relatively simple in construction and operation and once it has been started requires little or no maintenance or attention but continues to operate indefinitely withonly general supervision.

, Although I have disclosed herein the preferred practice and embodiment of my invention, I intend to cover aswell any change or modication I claim: In an apparatus for making uffed slag, the

`combination with a chain-bucket conveyor, of a 4*hopper for discharging wet slag fines into the conveyor buckets successively, means for continuously discharging molten slag into the buckets successively at a point beyond the hopper in the direction of bucket travel, a screen below the conveyor at the discharge end thereof adapted to receive fluied slag falling from the buckets as -they turn over successively, a return conveyor extending from below said screen to said hopper and means for wetting the slag fines which pass through the screen and fall on the return conveyor, as they approach the hopper.

'IRUMAN H. ICENNEDY.

References Cited in the le of this patent UNITED STATES PATENTS 

